1 /* 2 * wrtarga.c 3 * 4 * Copyright (C) 1991-1996, Thomas G. Lane. 5 * Modified 2015-2019 by Guido Vollbeding. 6 * This file is part of the Independent JPEG Group's software. 7 * For conditions of distribution and use, see the accompanying README file. 8 * 9 * This file contains routines to write output images in Targa format. 10 * 11 * These routines may need modification for non-Unix environments or 12 * specialized applications. As they stand, they assume output to 13 * an ordinary stdio stream. 14 * 15 * Based on code contributed by Lee Daniel Crocker. 16 */ 17 18 #include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */ 19 20 #ifdef TARGA_SUPPORTED 21 22 23 /* 24 * To support 12-bit JPEG data, we'd have to scale output down to 8 bits. 25 * This is not yet implemented. 26 */ 27 28 #if BITS_IN_JSAMPLE != 8 29 Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */ 30 #endif 31 32 /* 33 * The output buffer needs to be writable by fwrite(). On PCs, we must 34 * allocate the buffer in near data space, because we are assuming small-data 35 * memory model, wherein fwrite() can't reach far memory. If you need to 36 * process very wide images on a PC, you might have to compile in large-memory 37 * model, or else replace fwrite() with a putc() loop --- which will be much 38 * slower. 39 */ 40 41 42 /* Private version of data destination object */ 43 44 typedef struct { 45 struct djpeg_dest_struct pub; /* public fields */ 46 47 char *iobuffer; /* physical I/O buffer */ 48 JDIMENSION buffer_width; /* width of one row */ 49 } tga_dest_struct; 50 51 typedef tga_dest_struct * tga_dest_ptr; 52 53 54 LOCAL(void) 55 write_header (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, int num_colors) 56 /* Create and write a Targa header */ 57 { 58 char targaheader[18]; 59 60 /* Set unused fields of header to 0 */ 61 MEMZERO(targaheader, SIZEOF(targaheader)); 62 63 if (num_colors > 0) { 64 targaheader[1] = 1; /* color map type 1 */ 65 targaheader[5] = (char) (num_colors & 0xFF); 66 targaheader[6] = (char) (num_colors >> 8); 67 targaheader[7] = 24; /* 24 bits per cmap entry */ 68 } 69 70 targaheader[12] = (char) (cinfo->output_width & 0xFF); 71 targaheader[13] = (char) (cinfo->output_width >> 8); 72 targaheader[14] = (char) (cinfo->output_height & 0xFF); 73 targaheader[15] = (char) (cinfo->output_height >> 8); 74 targaheader[17] = 0x20; /* Top-down, non-interlaced */ 75 76 if (cinfo->out_color_space == JCS_GRAYSCALE) { 77 targaheader[2] = 3; /* image type = uncompressed grayscale */ 78 targaheader[16] = 8; /* bits per pixel */ 79 } else { /* must be RGB */ 80 if (num_colors > 0) { 81 targaheader[2] = 1; /* image type = colormapped RGB */ 82 targaheader[16] = 8; 83 } else { 84 targaheader[2] = 2; /* image type = uncompressed RGB */ 85 targaheader[16] = 24; 86 } 87 } 88 89 if (JFWRITE(dinfo->output_file, targaheader, 18) != (size_t) 18) 90 ERREXIT(cinfo, JERR_FILE_WRITE); 91 } 92 93 94 /* 95 * Write some pixel data. 96 * In this module rows_supplied will always be 1. 97 */ 98 99 METHODDEF(void) 100 put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, 101 JDIMENSION rows_supplied) 102 /* used for unquantized full-color output */ 103 { 104 tga_dest_ptr dest = (tga_dest_ptr) dinfo; 105 register JSAMPROW inptr; 106 register char * outptr; 107 register JDIMENSION col; 108 109 inptr = dest->pub.buffer[0]; 110 outptr = dest->iobuffer; 111 for (col = cinfo->output_width; col > 0; col--) { 112 outptr[0] = (char) GETJSAMPLE(inptr[2]); /* RGB to BGR order */ 113 outptr[1] = (char) GETJSAMPLE(inptr[1]); 114 outptr[2] = (char) GETJSAMPLE(inptr[0]); 115 inptr += 3, outptr += 3; 116 } 117 (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); 118 } 119 120 METHODDEF(void) 121 put_gray_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, 122 JDIMENSION rows_supplied) 123 /* used for grayscale OR quantized color output */ 124 { 125 tga_dest_ptr dest = (tga_dest_ptr) dinfo; 126 register JSAMPROW inptr; 127 register char * outptr; 128 register JDIMENSION col; 129 130 inptr = dest->pub.buffer[0]; 131 outptr = dest->iobuffer; 132 for (col = cinfo->output_width; col > 0; col--) { 133 *outptr++ = (char) GETJSAMPLE(*inptr++); 134 } 135 (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); 136 } 137 138 139 /* 140 * Write some demapped pixel data when color quantization is in effect. 141 * For Targa, this is only applied to grayscale data. 142 */ 143 144 METHODDEF(void) 145 put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, 146 JDIMENSION rows_supplied) 147 { 148 tga_dest_ptr dest = (tga_dest_ptr) dinfo; 149 register JSAMPROW inptr; 150 register char * outptr; 151 register JSAMPROW color_map0 = cinfo->colormap[0]; 152 register JDIMENSION col; 153 154 inptr = dest->pub.buffer[0]; 155 outptr = dest->iobuffer; 156 for (col = cinfo->output_width; col > 0; col--) { 157 *outptr++ = (char) GETJSAMPLE(color_map0[GETJSAMPLE(*inptr++)]); 158 } 159 (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); 160 } 161 162 163 /* 164 * Startup: write the file header. 165 */ 166 167 METHODDEF(void) 168 start_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo) 169 { 170 int num_colors, i; 171 FILE *outfile; 172 173 switch (cinfo->out_color_space) { 174 case JCS_GRAYSCALE: 175 /* Targa doesn't have a mapped grayscale format, so we will */ 176 /* demap quantized gray output. Never emit a colormap. */ 177 write_header(cinfo, dinfo, 0); 178 if (cinfo->quantize_colors) 179 dinfo->put_pixel_rows = put_demapped_gray; 180 else 181 dinfo->put_pixel_rows = put_gray_rows; 182 break; 183 case JCS_RGB: 184 if (cinfo->quantize_colors) { 185 /* We only support 8-bit colormap indexes, so only 256 colors */ 186 num_colors = cinfo->actual_number_of_colors; 187 if (num_colors > 256) 188 ERREXIT1(cinfo, JERR_TOO_MANY_COLORS, num_colors); 189 write_header(cinfo, dinfo, num_colors); 190 /* Write the colormap. Note Targa uses BGR byte order */ 191 outfile = dinfo->output_file; 192 for (i = 0; i < num_colors; i++) { 193 putc(GETJSAMPLE(cinfo->colormap[2][i]), outfile); 194 putc(GETJSAMPLE(cinfo->colormap[1][i]), outfile); 195 putc(GETJSAMPLE(cinfo->colormap[0][i]), outfile); 196 } 197 dinfo->put_pixel_rows = put_gray_rows; 198 } else { 199 write_header(cinfo, dinfo, 0); 200 dinfo->put_pixel_rows = put_pixel_rows; 201 } 202 break; 203 default: 204 ERREXIT(cinfo, JERR_TGA_COLORSPACE); 205 } 206 } 207 208 209 /* 210 * Finish up at the end of the file. 211 */ 212 213 METHODDEF(void) 214 finish_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo) 215 { 216 /* Make sure we wrote the output file OK */ 217 JFFLUSH(dinfo->output_file); 218 if (JFERROR(dinfo->output_file)) 219 ERREXIT(cinfo, JERR_FILE_WRITE); 220 } 221 222 223 /* 224 * The module selection routine for Targa format output. 225 */ 226 227 GLOBAL(djpeg_dest_ptr) 228 jinit_write_targa (j_decompress_ptr cinfo) 229 { 230 tga_dest_ptr dest; 231 232 /* Create module interface object, fill in method pointers */ 233 dest = (tga_dest_ptr) (*cinfo->mem->alloc_small) 234 ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(tga_dest_struct)); 235 dest->pub.start_output = start_output_tga; 236 dest->pub.finish_output = finish_output_tga; 237 238 /* Calculate output image dimensions so we can allocate space */ 239 jpeg_calc_output_dimensions(cinfo); 240 241 /* Create I/O buffer. Note we make this near on a PC. */ 242 dest->buffer_width = cinfo->output_width * cinfo->output_components; 243 dest->iobuffer = (char *) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, 244 JPOOL_IMAGE, (size_t) dest->buffer_width * SIZEOF(char)); 245 246 /* Create decompressor output buffer. */ 247 dest->pub.buffer = (*cinfo->mem->alloc_sarray) ((j_common_ptr) cinfo, 248 JPOOL_IMAGE, dest->buffer_width, (JDIMENSION) 1); 249 dest->pub.buffer_height = 1; 250 251 return &dest->pub; 252 } 253 254 #endif /* TARGA_SUPPORTED */ 255